System and method for operating a power tailgate system

ABSTRACT

A system for controlling a vehicle power tailgate includes a latch structured to be movable to a latching position when the latch is engaged with a portion of a tailgate so as to maintain the tailgate in a closed position associated with the latching position of the latch. A latch actuator operably connected to the latch to control operation of the latch. A memory is communicably coupled to the processor and stores a tailgate control module including instructions that when executed by a processor cause the processor to, responsive to receipt of a tailgate opening command, control operation of the latch actuator to attempt move the latch to an over-stroke position of the latch and, responsive to a failure to move the latch to the over-stroke position within a predetermined time period, control operation of the latch actuator to move the latch to a fully-latched position of the latch.

TECHNICAL FIELD

The embodiments disclosed herein relate to vehicles with power tailgate(PTG) systems and, more particularly, to a power tailgate systemincorporating a powered latch assembly operable to latch a tailgate in aclosed position responsive to a tailgate closing command, and operablecheck a tailgate for an overload condition prior to release of the latchto enable the tailgate to be opened, responsive to a tailgate openingcommand.

BACKGROUND

Many vehicles include tailgates. The tailgates serve as closure panels,and are movable between closed positions and open positions. In additionto the tailgates themselves, the vehicles include latch assemblies.Among other things, the latch assemblies include latches for latchingthe tailgates. To close the tailgates, the latches are activated. Whenthe latches are activated, the latches latch the tailgates as thetailgates are moved to the closed positions, and afterwards, when thetailgates are in the closed positions. To open the tailgates, thelatches are deactivated. When the latches are deactivated, the latchesunlatch the tailgates as the tailgates are moved to the open positions.

Many of today's vehicles with tailgates also include power tailgatesystems. The power tailgate systems include tailgate actuators for thetailgates, and latch actuators for the latch assemblies. By theoperation of the tailgate actuators and the latch actuators, the powertailgate systems automatically open the tailgates and automaticallyclose the tailgates. To automatically open the tailgates, the powertailgate systems open the tailgates after deactivating the latches. Toautomatically close the tailgates, the power tailgate systems close thetailgates after activating the latches.

Users may generate requests to automatically open the tailgate when,unbeknownst to them, there is loading on the tailgate. However, when thetailgate is overloaded, and the PTG system automatically opens thetailgate, the PTG system and/or any cargo in contact with the tailgatemay be damaged.

SUMMARY

In one aspect of the embodiments described herein, a system forcontrolling a vehicle power tailgate is provided. The system includes alatch structured to be movable to a latching position when the latch isengaged with a portion of a tailgate so as to maintain the tailgate in aclosed position associated with the latching position of the latch. Thesystem also includes a latch actuator operably connected to the latch tocontrol operation of the latch. The system also includes a processor anda memory communicably coupled to the processor and storing a tailgatecontrol module including instructions that when executed by theprocessor cause the processor to, responsive to receipt of a tailgateopening command, control operation of the latch actuator to attempt movethe latch to an over-stroke position of the latch and, responsive to afailure to move the latch to the over-stroke position within apredetermined time period, control operation of the latch actuator tomove the latch to a fully-latched position of the latch.

In another aspect of the embodiments described herein, a method isprovided, in a powered latch assembly for a vehicle tailgate, forchecking for an overload condition of a tailgate secured in a closedcondition by a latch prior to releasing the latch to enable opening ofthe tailgate. The method includes a step of, responsive to receipt of atailgate opening command, controlling operation of a latch actuator toattempt to move the latch to an over-stroke position over-stroke thelatch. The method also includes a step of, responsive to a failure tomove the latch to the over-stroke position within a predetermined timeperiod, controlling operation of the latch actuator to move the latch toa fully-latched position. The method also includes a step of, responsiveto moving the latch to the over-stroke position within the predeterminedtime period, controlling operation of the latch actuator to move thelatch to a release position enabling opening of the tailgate.

In yet another aspect of the embodiments described herein, anon-transitory computer-readable medium is provided for controllingoperation of a vehicle power tailgate system to check a tailgate securedin a closed condition by a latch for an overload condition prior toreleasing the latch, to enable opening of the tailgate. The mediumstores instructions that when executed by one or more processors causethe one or more processors to, responsive to receipt of a tailgateopening command, control operation of a latch actuator to attempt tomove the latch to an over-stroke position of the latch; responsive to afailure to move the latch to the over-stroke position within apredetermined time period, control operation of the latch actuator tomove the latch to a fully-latched position; and responsive to moving thelatch to the over-stroke position within the predetermined time period,control operation of the latch actuator to move the latch to a releaseposition enabling opening of the tailgate.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate various systems, methods, andother embodiments of the disclosure. It will be appreciated that theillustrated element boundaries (e.g., boxes, groups of boxes, or othershapes) in the figures represent one embodiment of the boundaries. Insome embodiments, one element may be designed as multiple elements ormultiple elements may be designed as one element. In some embodiments,an element shown as an internal component of another element may beimplemented as an external component and vice versa. Furthermore,elements may not be drawn to scale.

FIGS. 1A and 1B are schematic perspective views of portions of a vehicleincluding a cargo bed, a tailgate, tailgate-side latch assemblies inaccordance with an embodiment described herein that include latches forlatching the tailgate, vehicle-side strikers for the latches, a powertailgate system that includes tailgate actuators for the tailgate, andlatch actuators for the latch assemblies.

FIG. 1C is a schematic block diagram of a vehicle including a powertailgate system incorporating a powered latch assembly in accordancewith an embodiment described herein.

FIG. 1D is a schematic perspective view from a rear of the vehicleshowing one example of a condition in which cargo may overload a closedtailgate.

FIG. 2A is a schematic perspective view of a latch assembly inaccordance with an embodiment described herein, including a coverstructured for protecting operating components of the latch assemblyfrom contaminants.

FIG. 2B is a schematic side view of the latch assembly embodiment shownin FIG. 2A.

FIG. 3A is a schematic perspective view of the operating components andmechanism of a latch assembly in accordance with an embodiment describedherein.

FIG. 3B is a schematic side view of a portion of the latch assembly ofFIG. 3A.

FIG. 3C is a schematic perspective view of the components and mechanismin FIG. 3A shown mounted in a cover (with a portion of the coverpartially cut away) structured to environmentally isolate the latch fromthe other components.

FIG. 4 is a schematic plan view of a connecting structure in accordancewith an embodiment described herein, usable for connecting a latch ofthe latch assembly to a latch control member of the latch assembly.

FIGS. 5A and 5B are the views of the latch assembly mechanism of thelatch assembly shown in FIGS. 3A and 3B, which represents the latchassembly in an idle configuration when the tailgate is open and thelatch is not in contact with a striker of the tailgate.

FIGS. 6A and 6B are views of the latch assembly mechanism similar to theviews shown in FIGS. 5A and 5B, showing a configuration of the latchassembly when the latch is in a half-latched position engaging arespective tailgate striker to maintain the tailgate in a near-closedposition.

FIGS. 7A and 7B are views of the latch assembly mechanism similar to theviews shown in FIGS. 6A and 6B, showing a configuration of the latchassembly during movement of the latch from the half-latched position toa fully-latched position.

FIGS. 8A and 8B are views of the latch assembly mechanism similar to theviews shown in FIGS. 7A and 7B, showing a configuration of the latchassembly when the latch is in a fully-latched position engaging thetailgate striker to maintain the tailgate in a fully-closed position,and the sector gear, pawl crank, pawl lever, and latch lever are inrespective idle positions prior to moving of the latch to an over-strokeposition.

FIGS. 9A and 9B are views of the latch assembly mechanism similar to theviews shown in FIGS. 8A and 8B, showing a configuration of the latchassembly when the latch is in an over-stroke position engaging thetailgate striker to maintain the tailgate in an over-closed position.

FIGS. 10A and 10B are the views of the latch assembly mechanism in FIGS.8A and 8B after the latch has returned from the over-stroke position ofFIGS. 9A-9B to the fully-latched position.

FIGS. 11A and 11B are views of the latch assembly mechanism similar tothe views shown in FIGS. 8A and 8B, but showing a configuration of thelatch assembly after a pawl of the latch assembly has been disengagedfrom a latch control member of the latch assembly responsive to atailgate opening command, thereby releasing the latch to rotate in anunlatching direction.

FIGS. 12A and 12B are views of the latch assembly mechanism similar tothe views shown in FIGS. 5A and 5B, showing the latch assembly mechanismafter returning to the idle configuration after the latch has beenreleased and the tailgate has been opened.

FIG. 13 is a flow diagram showing a method of operation of the latchassembly to overload check the tailgate.

DETAILED DESCRIPTION

This disclosure relates to a vehicle that includes a tailgate, a latchfor latching the tailgate, and as part of a power tailgate system, alatch actuator connected with the latch. In relation to the vehicle,this disclosure teaches systems and methods for operating the powertailgate system. According to the systems and methods, the powertailgate system may overload check the tailgate using the latch actuatorto come to a determination whether the tailgate is overloaded or notoverloaded, and when the tailgate is overloaded, deny requests toautomatically open the tailgate.

Part of a representative passenger vehicle 100 is shown in FIG. 1A. Asshown, the vehicle 100 is a pickup truck. The vehicle 100 includes anexterior and a number of interior compartments. In the illustratedpickup truck configuration of the vehicle 100, the compartments includean open-topped bed 102 for carrying cargo. In addition to the bed 102,the compartments may include a passenger compartment, an enginecompartment and the like. Among other things, the vehicle 100 mayinclude seats, a dash assembly, an instrument panel and the like housedin the passenger compartment. In addition, the vehicle 100 may includean engine, a motor, a transmission and the like, as well as otherpowertrain components, such as wheels, housed in the engine compartmentand elsewhere in the vehicle 100. The wheels support the remainder ofthe vehicle 100 on the ground. One, some or all of the wheels arepowered by the remainder of the powertrain components to drive thevehicle 100 along the ground.

The vehicle 100 includes a body 104 that forms the exterior and definesor otherwise encloses the bed 102 and the other compartments. Inrelation to the bed 102, the body 104 includes a deck 106, two sides108, a bulkhead 110 and a rear end 112. At the rear end 112, the body104 defines a tailgate opening 114. Likewise, the body 104, includingbut limited to the sides 108, renders surrounding body 116 that framesthe tailgate opening 114. The tailgate opening 114 opens between the bed102 and the exterior. Relatedly, as part of the rear end 112, the body104 includes a tailgate 118 corresponding to the tailgate opening 114.This description follows with reference to the tailgate 118 in theillustrated pickup truck configuration of the vehicle 100. However, itwill be understood that this disclosure is applicable in principle tootherwise similar vehicles whose bodies include tailgates correspondingto tailgate openings that open between their compartments and theirexteriors. For instance, this disclosure is applicable in principle tovehicles whose bodies include liftgates corresponding to liftgateopenings that open between their cargo compartments and their exteriors.

As shown with additional reference to FIG. 1B, the tailgate 118 servesas closure panel for the bed 102. The tailgate 118 is pivotallyconnected to the surrounding body 116 for movement, relative to thetailgate opening 114, between one or more closed positions and one ormore open positions. In FIG. 1A, the tailgate 118 is shown in arepresentative closed position. In the closed positions, the tailgate118 is positioned over the tailgate opening 114, with the periphery ofthe tailgate 118 adjacent the surrounding body 116. In FIG. 1B, thetailgate 118 is shown in a representative open position. In the openpositions, the tailgate 118 is positioned away from the tailgate opening114, which allows access to the bed 102 from the rear of the vehicle100.

As shown with additional reference to FIG. 1C, the vehicle 100 includesone or more vehicle systems 130 operable to perform vehicle functions.In addition to the vehicle systems 130, the vehicle 100 includes asensor system 132, as well as one or more processors 134, memory 136,and a control module 138 to which the vehicle systems 130 and the sensorsystem 132 are communicatively connected. The control module 138 may behoused, in whole or in part, in the tailgate 118. The sensor system 132is operable to detect information about the vehicle 100. The processors134, the memory 136 and the control module 138 together serve as acomputing device whose control module 138 is employable to orchestratethe operation of the vehicle 100, in whole or in part. Specifically, thecontrol module 138 operates the vehicle systems 130 based on informationabout the vehicle 100. Accordingly, as a prerequisite to operating thevehicle systems 130, the control module 138 gathers information aboutthe vehicle 100, including the information about the vehicle 100detected by the sensor system 132. The control module 138 then evaluatesthe information about the vehicle 100, and operates the vehicle systems130 based on its evaluation.

The vehicle systems 130 are part of, mounted to, or otherwise supportedby the body 104. Each vehicle system 130 includes one or more vehicleelements. On behalf of the vehicle system 130 to which it belongs, eachvehicle element is operable to perform, in whole or in part, anycombination of vehicle functions with which the vehicle system 130 isassociated. It will be understood that the vehicle elements, as well asthe vehicle systems 130 to which they belong, may but need not bemutually distinct.

The vehicle systems 130 include an energy system 140 and a powertailgate system 142. The power tailgate system 142 is connected to theenergy system 140. Moreover, the power tailgate system 142 is connectedto the tailgate 118, and to the latch assemblies 120. The energy system140 is operable to perform one or more energy functions, including butnot limited to storing and otherwise handling electrical energy. Thepower tailgate system 142 is operable to perform one or more powertailgate functions using electrical energy from the energy system 140,including but not limited to automatically opening the tailgate 118 andautomatically closing the tailgate 118.

Among the power tailgate elements of the power tailgate system 142, thevehicle 100 includes one or more tailgate actuators 150 for the tailgate118. Each tailgate actuator 150 may be housed, in whole or in part, inthe surrounding body 116. In one implementation, each tailgate actuator150 is a motor-driven spindle drive. In this and other implementations,each tailgate actuator 150 is connected to the energy system 140.Moreover, each tailgate actuator 150 is connected with the tailgate 118.The tailgate actuators 150 are operable to open the tailgate 118, closethe tailgate 118 and otherwise move the tailgate 118 between the closedpositions and the open positions using electrical energy from the energysystem 140. Although the vehicle 100, as shown, includes two tailgateactuators 150 in the power tailgate system 142, it will be understoodthat this disclosure is applicable in principle to otherwise similarvehicles 100 including one or more tailgate actuators 150 in the powertailgate system 142.

Also among the power tailgate elements of the power tailgate system 142,the vehicle 100 includes one or more latch actuators 152 for the latchassemblies 120. Each latch actuator 152 corresponds to a latch assembly120, and may be housed, in whole or in part, in the tailgate 118. Forinstance, each latch actuator 152 may be housed in the tailgate 118, andconnected to the tailgate 118, as a unitary module with thecorresponding latch assembly 120. In one implementation, each latchactuator 152 is a motor-driven reduction drive. In this and otherimplementations, each latch actuator 152 is connected to the energysystem 140. Moreover, each latch actuator 152 is operably connected withthe corresponding latch assembly 120 and an associated latch 124. Theterm “operably connected,” as used throughout this description, caninclude direct or indirect connections, including connections withoutdirect physical contact. Similarly, elements described as being“operably connectible” are elements that can be connected directly(through direct physical contact) or indirectly, through other,physically intermediate element(s). For each corresponding latchassembly 120, latch 124 and latch actuator 152, using electrical energyfrom the energy system 140, the latch actuator 152 is operable toactivate the latch 124 for non-revertible movement in the latchingdirection, and deactivate the latch 124 for movement in the unlatchingdirection. Moreover, the latch actuator 152 is operable to disengage thepawl 202 from the latch 124, move the latch 124 in the latchingdirection, and move the latch 124 in the unlatching direction. In one ormore arrangements, the latch may be released or deactivated bydisengaging the latch control member 125 from direct physical contactwith any element (i.e., in the mechanism shown, the pawl 202 and thelatch lever 220) of the control linkage 206 structured to control itsmotion, so that the latch may be acted on only by the latch controlmember spring 200. Although the vehicle 100, as shown, includes onelatch actuator 152 per latch assembly 120 in the power tailgate system142, it will be understood that this disclosure is applicable inprinciple to otherwise similar vehicles 100 including one or more latchactuators 152 per latch assembly 120 in the power tailgate system 142.

The vehicle 100 includes one or more user controls 154 and one or moreuser interfaces 156 for the power tailgate system 142. In the vehicle100, the user controls 154 and the user interfaces 156 may be part of aninfotainment system typical of vehicles, or dedicated to the powertailgate system 142. The user controls 154 serve as interfaces betweenusers and the vehicle 100 itself, and are operable to receivemechanical, verbal and other user inputs for generating requests.Similarly, the user interfaces 156 serve as interfaces between users andthe vehicle 100 itself, and are operable to issue tactile, sound andvisual outputs that may be sensed by users. For instance, the vehicle100 may include one or more onboard or off-board user controls 154 forremotely generating requests to automatically open the tailgate 118 fromin the passenger compartment or otherwise away from the tailgate 118(e.g., an onboard user control 154 in the passenger compartment, anoff-board user control 154 located away from the tailgate 118, etc.).For instance, the vehicle 100 may include one or more onboard oroff-board user controls 154 for non-remotely generating requests toautomatically open the tailgate 118 from the rear of the vehicle 100 orotherwise adjacent the tailgate 118 (e.g., an onboard user control 154on the rear of the vehicle 100, an off-board user control 154 locatedadjacent the tailgate 118, etc.).

As part of the sensor system 132, the vehicle 100 includes one or moreonboard sensors. The sensors monitor the vehicle 100 in real-time. Thesensors, on behalf of the sensor system 132, are operable to detectinformation about the vehicle 100, including information about theoperation of the vehicle 100. Among the sensors, the vehicle 100includes one or more tailgate sensors, one or more latch sensors, one ormore controller area network (CAN) sensors and the like. Relatedly,among information about the operation of the vehicle 100, the sensorsystem 132 is operable to detect the movement of the tailgate 118, themovement of the latches 124, requests to automatically open the tailgate118, requests to automatically close the tailgate 118, and theoperational statuses of one, some or all of the vehicle systems 130,including the energy system 140, the tailgate actuators 150 and thelatch actuators 152.

Referring to FIGS. 1A-3B, in relation to opening the tailgate 118 andclosing the tailgate 118, the vehicle 100 includes one or moretailgate-side latch assemblies 120. Each latch assembly 120 includes astriker chute 122, and a corresponding latch 124 for latching thetailgate 118. Relatedly, the vehicle 100 includes one or morevehicle-side strikers 126 corresponding to the striker chutes 122 andthe latches 124. Each latch assembly 120 is connected to the tailgate118. Each latch assembly 120 may be housed, in whole or in part, in thetailgate 118. For instance, each latch assembly 120 may be housed in thetailgate 118, and connected to the tailgate 118, as a unitary module.Each striker 126 is connected to the surrounding body 116. Although thevehicle 100, as shown, includes two latch assemblies 120 and twostrikers 126, it will be understood that this disclosure is applicablein principle to otherwise similar vehicles 100 including one or morelatch assemblies 120 and one or more strikers 126.

Each latch assembly 120 includes one or more latch components, includingbut not limited to the striker chute 122 and the latch 124. The latchcomponents are connected within the latch assembly 120, and equally,connected within the tailgate 118. From within the latch assembly 120,and equally, from within the tailgate 118, some of the latch components,including but not limited to the striker chute 122, may be immovable.These latch components are not only immovable relative to one another,but also immovable relative to the latch assembly 120, and equally,immovable relative to the tailgate 118. In addition, some of the latchcomponents, including but not limited to the latch 124, may be movable.These latch components are not only movable relative to one another, butalso movable relative to the latch assembly 120, and equally, movablerelative to the tailgate 118. In any event, all of the latch components,including but not limited to the striker chute 122 and the latch 124,are co-movable with the latch assembly 120, and equally, co-movable withthe tailgate 118. With respect to the movement of the latch components,this description follows with reference to the perspective of thetailgate 118. However, it will be understood that this disclosure isapplicable in principle to the perspective of the latch assembly 120.

For each corresponding striker chute 122, latch 124 and striker 126, thestriker chute 122 opens to the tailgate 118 for passing the striker 126into and out of the tailgate 118. The latch 124 is movable, relative tothe striker chute 122, in a latching direction EE (FIG. 3B) and in anunlatching direction AA between one or more unlatching positions and oneor more latching positions. In FIGS. 1B and 3A-3C, the latch 124 isshown in a representative unlatching position. In the unlatchingpositions, the latch 124 aligns with the striker chute 122 for passingthe striker 126 into and out of the tailgate 118. In the latchingpositions, the latch 124 crosses the striker chute 122 for capturing thestriker 126 within the tailgate 118. Accordingly, the latch 124 latchesthe tailgate 118 to the surrounding body 116 against the striker 126.

The latch 124 may be activated for non-revertible movement in thelatching direction EE. When the tailgate 118 is being closed, the latch124 functions as the tailgate 118 is moved to the closed positions, andafterward, when the tailgate 118 is in the closed positions. With thetailgate 118 in the open positions, the latch 124, having previouslyunlatched the tailgate 118, is in an unlatching position. To close thetailgate 118, the latch 124 is activated for non-revertible movement inthe latching direction. As the tailgate 118 is moved to the closedpositions, the striker 126 passes into the tailgate 118 through thestriker chute 122. The latch 124 may include a slot 124 b structured toreceive therein an associated striker 126 mounted on the vehicle, toengage the striker so as to secure the tailgate 118 in a closedposition. As it passes into the tailgate 118, the striker 126 moves thelatch 124 in the latching direction to a latching position, and thelatch 124, unable to move in the unlatching direction to an unlatchingposition, latches the tailgate 118 to the surrounding body 116 againstthe striker 126.

In addition, the latch 124 may be deactivated for movement in theunlatching direction. When the tailgate 118 is being opened, the latch124 functions as the tailgate 118 is moved to the open positions. Withthe tailgate 118 in the closed positions, the latch 124, havingpreviously latched the tailgate 118, is in a latching position. To openthe tailgate 118, the latch 124 is deactivated for movement in theunlatching direction. As the tailgate 118 is moved to the openpositions, the striker 126 passes out of the tailgate 118 through thestriker chute 122. As it passes out of the tailgate 118, the striker126, in combination with a bias of the latch 124 for movement in theunlatching direction, moves the latch 124 in the unlatching direction AAto an unlatching position, and the latch 124 unlatches the tailgate 118from the surrounding body 116 from against the striker 126.

A representative latch assembly 120, with a cover 301 (described ingreater detail below) removed to better view movable latch components,is shown in FIGS. 3A and 3B. As shown, the latch assembly 120 isrendered by shaft-supported rotary latch components. Various componentsof the latch assembly may be rotatably mounted to any portion orstructure of the latch assembly enabling the relative positionalarrangements of the components and the functional arrangements betweenthe components as described herein to be maintained during operation ofthe latch assembly.

As shown with reference to a phantom rendering of the striker chute 122shown in FIG. 3B, among the movable latch components of the latchassembly 120, the tailgate 118 includes the latch 124, as noted above,as well as a latch spring 200 for exerting a biasing force on the latch124 in the direction indicated by arrow AA in FIG. 3B. Latch 124 may bestructured to engage striker 126 and to be rotatable into a latchingposition when engaged with the striker, so as to maintain the tailgatein a closed position of the tailgate associated with the latchingposition of the latch.

The latch assembly may include a latch control member 125 rotationallyconnected to the latch 124 and structured to be engageable by a pawl 202of the latch assembly to maintain the latch control member 125 in aposition associated with a latching position of the latch 124.“Rotationally connected” means that the latch control member 125 and thelatch 124 are connected so as to rotate in correspondence with eachother (e.g., a rotation of the latch control member 30° in a firstdirection will produce an associated rotation of the latch 30° in thefirst direction, and vice versa).

The latch control member 125 may be biased for rotation in direction AA(i.e., in the unlatching direction of the latch 124) by associatedbiasing spring 200. When the latch control member 125 is engaged by thepawl 202, the latch control member 125 is prevented from rotating in theopening direction of the latch (i.e., direction AA as shown in FIGS. 3Aand 3B). As mounted in the latch assembly 120, the latch control member125 may be cooperatively structured, oriented, and rotationallyconnected with respect to the latch 124 so that latch control member 125features engageable by the pawl 202 correspond to associated latchingpositions of the latch 124. By this structure, each latching position ofthe latch 124 may be maintained by the pawl 202 engaging an associatedfeature on the latch control member 125 during rotation of the latchcontrol member 125 and latch. Similarly, rotation of the pawl 202 out ofengagement with the latch control member 125 may release the latchcontrol member 125 (and the rotationally-attached latch 124) forrotation in unlatching direction AA responsive to the biasing forceexerted by the latch control member spring 200.

In one or more arrangements, the latch control member 125 may be formedas a separate piece from the latch 124. In one or more arrangements, thelatch control member 125 may be mounted in the latch assembly so thatthe rotational axis of the latch control member 125 is coaxial with therotational axis of the latch, and so that the latch is axially spacedapart from the latch control member 125 along the common rotational axisX1. Thus, because the latch control member 125 and latch 124 arecoaxially mounted, the latch control member 125 is coaxiallyrotationally connected to the latch 124 and structured to be engageableby the pawl 202 of the latch assembly to maintain the latch controlmember 125 in a position associated with the latching position of thelatch 124.

Pawl 202 may be mounted in the latch assembly 120 so as to be rotatablewith respect to the latch control member 125. A pawl spring 204 mayexert a rotational force on the pawl 202 in a direction DD biasing thepawl toward contact with the latch control member 125. The pawl 202 maybe structured and positioned to prevent rotation of the latch controlmember 125 in direction AA (i.e., the unlatching direction of the latch124) when the pawl 202 is in contact with the latch control member 125.As described above, the contact between the pawl 202 and the latchcontrol member 125 may also maintain the rotationally connected latch124 in the half-latched and fully-latched positions described herein.

The latch assembly 120 may also include a control linkage 206 structuredfor controlling rotation of the pawl 202 and latch control member 125.The control linkage 206 may include a sector gear 212 having a drive pin214 extending therefrom at a fixed location so as to rotate with thesector gear. The sector gear 212 may be structured and positioned sothat rotation of the sector gear in direction BB causes the drive pin214 to engage the latch lever 220, thereby producing a rotation of thelatch lever in direction BB. The sector gear 212 may also be structuredand positioned so that rotation of the sector gear in a direction EEopposite the direction BB causes the drive pin 214 to engage the pawlcrank 216, thereby producing a rotation of the pawl crank in directionBB. The sector gear 212 is engaged with, and rotatable by, a pinion gear210 coupled to an associated latch actuator 152 for powering the latchassembly 120.

The control linkage 206 may also include latch lever 220 mounted in thelatch assembly so as to be rotatable with respect to the sector gear212. The latch lever 220 may fully control member 125 in direction DD.The latch lever 220 may also be rotated in direction FF to disengagefrom the latch control member 125.

The control linkage 206 may also include the pawl crank 216, which maybe structured and positioned so as to be rotatable with respect to thesector gear 212. When the pawl crank 216 is rotated in direction BB bycontact with the rotating drive pin (rotating in direction EE), the pawlcrank 216 may engage the pawl lever 218 to rotate the pawl lever indirection EE.

The control linkage 34 may also include the pawl lever 218 structuredand positioned to be rotatable to engage the pawl 202. Rotation of thepawl lever 218 may be biased in the direction BB by an associated pawllever spring 204. Rotation of the pawl lever 218 in direction EE mayproduce a rotation of the pawl 202 in direction AA so as to disengagethe pawl from the latch control member 125, thereby allowing the latchcontrol member 125 to rotate in direction AA to an unlatching positionresponsive to a force exerted by the latch control member 125 biasingspring 200.

In FIGS. 3A and 3B, the latch 124 is shown in a representativeunlatching position. The latch control member 125 is biased, by thelatch control member spring 200, for movement in the unlatchingdirection. The pawl 202 is biased, by the pawl spring 204, forengagement with the latch control member 125. In FIGS. 3A and 3B, thepawl 202 is shown engaging the latch control member 125. When the pawl202 engages the latch control member 125, the latch 124 rotationallyconnected to the latch control member 125 is non-revertibly movable inthe latching direction (i.e., the latch is only permitted to move in thelatching direction). When the pawl 202 disengages from the latch controlmember 125 (i.e., when the pawl is rotated so as to be out of physicalcontact with the latch control member 125), the attached latch controlmember 125 and latch 124 are rotatable in the unlatching direction AAunder influence of the latch control member spring. Accordingly, in anormally-activated configuration, the pawl 202 normally engages thelatch control member 125, and with the pawl 202 normally engaging thelatch control member 125, the latch 124 is normally activated fornon-revertible movement in the latching direction. Likewise, the latch124 is deactivated for movement in the unlatching direction (responsiveto the biasing force exerted by latch control member spring 200) whenthe pawl 202 is disengaged from the latch control member 125.

The corresponding latch actuator 152 for the latch 124 is connected withthe control linkage 206 through the pinion gear 210. The latch actuator152 is operable to drive the control linkage 206 using electrical energyfrom the energy system 140.

As shown, the control linkage 206 includes a pinion gear 210 meshed withthe sector gear 212. The latch actuator 152 is connected with thecontrol linkage 206 at the pinion gear 210, and is operable to drive thecontrol linkage 206 through the pinion gear 210 using electrical energyfrom the energy system 140.

In FIGS. 3A and 3B, the control linkage 206 is shown idled after havingbeen driven by the latch actuator 152 to disengage the pawl 202 anddisengage the latch 124. Through the pinion gear 210, the sector gear212, the drive pin 214, the pawl crank 216 and the pawl lever 218, thecontrol linkage 206 is drivable by the latch actuator 152 by moving thepinion gear 210 in the direction indicated by arrow BB until the pawllever 218 disengages the pawl 202 from the latch control member 125, andthereafter, in the direction EE opposite direction BB until the pawllever 218 disengages from the pawl 202.

Alternatively, through the pinion gear 210, the sector gear 212, thedrive pin 214 and the latch lever 220, the control linkage 206 isdrivable by the latch actuator 152 by moving the pinion gear 210 in thedirection indicated by arrow EE until the latch lever 220 moves thelatch 124 in the latching direction, and thereafter, in the directionindicated by arrow BB until the latch lever 220 disengages from thelatch 124 after moving the latch 124 in the latching direction.

Referring to FIGS. 2A, 2B, and 3C, in one or more arrangements, thelatch assembly 120 may include a cover 301 having a first wall 301 a.The first wall 301 a may serve to physically isolate and environmentallyseparate the latch 124 from a space in which other elements of the latchmechanism (such as the control linkage 206 and the pawl 202) arepositioned, thereby preventing contaminants from reaching elements ofthe latch mechanism other than the latch. To this end, in one or morearrangements, the control linkage 206 may be mounted in the latchassembly 120 so that the control linkage resides along a first side 301s of the first wall 301 a in a position where the control linkage 206 isoperably engageable with the pawl 202. A component or group ofcomponents is considered to be “operably engageable” with anothercomponent or group of components when at least one component of thecomponent/group of components is structured and positioned so as enablephysical contact between the two components or groups of components forperforming the latching and unlatching operations described herein. Thepawl 202 and the control linkage 206 may also be mounted in the latchassembly 120 so that the pawl resides along a first side 301 s of thefirst wall 301 a of the cover 301. In addition, the latch control member215 may be mounted in the latch assembly 120 so that the latch controlmember resides along the first side 301 s of the first wall 301 a in aposition where the latch control member 125 is operably engageable withthe pawl 202 and the control linkage 206. The latch 124 may berotationally connected to the latch control member 125 through anopening provided in the first wall 301 a as described herein, with thelatch 124 being positioned along a second side 301 t of the first wall301 a opposite the first side 301 s of the first wall.

Referring to FIGS. 3A-3C, in one or more particular arrangements, thecover 301 may define an enclosure 303 structured for mounting thereinvarious components of the latch assembly. In particular arrangements,the first wall 301 a may be part of the enclosure 303. Thus, theenclosure 303 may be bounded along a side thereof by the first wall 301a. In one or more arrangements, the cover 301 may include a second wall301 b connected to the first wall 301 a. In one or more arrangements,the cover 301 may also include a third wall 301 c connected to the firstwall 301 a and positioned opposite the second wall 301 b. Incombination, the first, second, and third walls (and also portion(s) ofone or more additional walls and/or portions of other latch assemblycomponents) may define boundaries of the enclosure 303.

In one or more arrangements, the latch control member 125 may be mountedin the latch assembly 120 so as to reside inside the enclosure 303. Inone or more arrangements, as seen in FIG. 3C, the control linkage 206and the pawl 202 may also be mounted in the latch assembly 120 so as toreside within the enclosure 303. Also, as seen in FIGS. 2B and 3C, thesecond wall 301 b may have an opening 301 d enabling access from anexterior of the enclosure to the pinion gear 210, so that an associatedlatch actuator 152 may engage the pinion gear 210 to power the latchassembly.

In one or more arrangements, the latch control member 125 may be mountedin the latch assembly 120 along a first side 301 s of the first wall 301a and the latch 124 may be mounted in the latch assembly 120 along asecond side 301 t of the first wall 301 a opposite the first side 301 s.Referring to FIGS. 3C and 4 , a connecting structure 320 may extendthrough the cover first wall 301 a to rotationally connect the latchcontrol member 125 and latch 124. In one or more arrangements, theconnecting structure 320 may include an internally-splined hole 320 aformed enclosing a rotational axis X1 of the latch control member 125.An externally-splined bushing 320 b may have splines structured forcomplementary engagement with the internal splines of latch controlmember hole 320 a. The bushing 320 b may be received in the hole 320 aand may be secured in the hole using an interference fit, a fastener,welding, or by any other suitable method.

The connecting structure 320 may also include an internally-splinedbushing 320 c having internal splines structured for complementaryengagement with the external splines of the bushing 320 b. The bushing320 c may be structured to extend through a hole 124 a formed in thelatch 124 and also through a hole 301 v formed in first wall 310 a. Thehole 301 v and the bushing 320 c may be dimensioned so as to form aclose sliding fit between the bushing and the first wall, to allowrotation of the bushing with respect to the first wall while alsopreventing moisture, dirt, and other contaminants from passing throughthe hole from the second side of the first wall to the first side of thefirst wall where the contaminants may interfere with operation of thelatch assembly or damage latch assembly components.

In one or more arrangements, the cover 301 may also include a supportwall 330 connected to the first wall 301 a and spaced apart from thefirst wall. As seen in the drawings, the latch 124 may be positionedbetween the first wall 301 a and the support wall 330 when the latch 124is mounted in the latch assembly. The support wall 330 may include astriker chute 122 formed therein and configured for receiving thestriker 126 during operation of the latch assembly. Referring to FIGS.2A, 2B, and 4 the latch 124 in the space between the first wall 301 aand the support wall 330 may be exposed to contaminants from the vehicleexterior environment entering the striker chute 122.

In one or more arrangements, an end 320 d of the latch bushing 320 c mayextend through the hole 124 a in the latch 124 and may be rotatablysecured in a hole 330 b formed in the support wall. The support wall 330may be firmly positionally fixed with respect to the first wall 301 a sothat the support wall 330 may be used to help rotatably support thelatch 124 and connecting structure 320 against forces exerted on thelatch 124 by the striker 126 during operation of the latch assembly.

FIGS. 5A-12B show a progression of configurations of the latch assemblyduring various stages of operation, proceeding starting from an openposition of the tailgate (FIGS. 5A-5B) to a fully-closed condition ofthe tailgate (FIGS. 8A-8B) and then to an over-closed position of thetailgate in which the latch is over-stroked (FIGS. 9A-9B), thenproceeding back to the closed tailgate/fully-latched position (FIGS.10A-10B). After this, the latch control member 125 may be released fromcontact with the pawl (FIGS. 11A-11B) to enable the latch 124 to rotateto an open position as the tailgate opens (FIGS. 12A-12B).

During operation, the control module 138 gathers information about thevehicle 100 for evaluation, including the movement of the tailgate 118,the movement of the latch 124, requests to automatically open thetailgate 118, requests to automatically close the tailgate 118, theoperational statuses of the energy system 140, the tailgate actuator 150and the latch actuator 152, and other information about the vehicle 100detected by the sensor system 132. For instance, with respect to themovement of the latch 124, the control module 138 monitors for andidentifies unlatching events indicating movement of the latch 124 to theunlatching position Likewise, the control module 138 monitors for andidentifies half-latched events and fully-latched events indicatingmovement of the latch 124 to the half-latched position and to thefully-latched position. The control module 138 may also monitor for andidentify an over-closed position of the tailgate indicating movement ofthe match to an over-stroke position as described herein. For instance,with respect to the operational statuses of the energy system 140 andthe latch actuator 152, the control module 138 monitors for andidentifies the load on the latch actuator 152, such as the electricalenergy drawn by the latch actuator 152 from the energy system 140, thespeed of the latch actuator 152 and the like, associated with theoperation of the latch actuator 152.

Referring now to FIGS. 5A-7B, a process of closing and latching thetailgate will be described.

FIGS. 5A-5B show the latch assembly in the idle configuration of FIGS.3A-3C. In FIGS. 5A-5B, the latch 124 is in the unlatching position andactivated for non-revertible movement in the latching direction.Accordingly, the latch 124 is movable in the latching direction from theunlatching position to the half-latched position, and thereafter, is notmovable in the unlatching direction past the half-latched position.

In response to a request to automatically close the tailgate 118, thecontrol module 138 may operate the tailgate actuator 150 to close thetailgate 118 until the tailgate 118 reaches the near-closed position. Asthe tailgate 118 is moved to the near-closed position, the striker 126passes into the tailgate 118 through the striker chute 122 (FIG. 5B). Asit passes into the tailgate 118, the striker 126 rotates the latch 124in the latching direction EE from the unlatching position toward thehalf-latched position. Because the latch control member 125 isrotationally connected to the latch 124, the latch control member 125(which is in engagement with the pawl 202) rotates in correspondencewith the latch. This rotation continues until the latch 124 reaches thehalf-latched position (FIGS. 6A-6B), at which time the connected latchcontrol member 125 engages a surface of the pawl 202 designed to preventback-rotation of the latch control member 125 and the attached latch inthe unlatching direction AA and back toward the unlatch position of thelatch. The latch 124 is now activated for non-revertible movement in thelatching direction EE by its rotational connection to the latch controlmember 125 and by the engagement between the latch control member 125and the pawl 202.

In addition, referring to FIGS. 6A-6B and in one or more arrangements,the latch 124 may be structured so that, with respect to a verticalplane V1 extending through the common rotational axis X1, a centroid C1of a cross-section of the striker 126 taken through a portion 126 p ofthe striker residing inside the slot 124 b resides along a first side S1of the plane V1 when the latch 124 is in a half-latched position. In oneor more particular arrangements, and as shown in FIGS. 6A-6B, the latch124 may be structured so that, with respect to the vertical plane V1,the entire cross-section of the striker 126 taken through the portion126 p of the striker residing inside the slot 124 b resides along thefirst side S1 of the plane V1 when the latch 124 is in the half-latchedposition.

In one or more arrangements, and as shown in the drawings, across-section of the striker 126 taken through the portion 126 p of thestriker residing within the latch slot 124 b may be a circular cross-section. However, the cross-section of the portion 126 p of the striker126 residing within the latch slot 126 b may have any of a variety ofother shapes.

Also, as seen in FIG. 6B, the latch slot 124 b may be bounded by a flatbearing edge 124 e structured to engage the striker 126 to move thetailgate 118 in a direction toward an over-closed position of thetailgate when the latch moves in the latching direction EE. In addition,the latch 124 may be structured so that a plane P2 extending through thelatch rotation axis X1 and parallel to a plane P3 defined by the slotbearing edge 124 e resides outside the slot 124 b. This structuralarrangement allows the slot 124 b to have a greater depth within a givenspace envelope of the latch, thereby helping to minimize the spaceoccupied by the latch during operation. This aids in maximizing theachievable effective stroke length of the striker 126 during rotation ofthe latch 124 in the latching direction EE to draw the striker towardthe fully-latched and over-stroke positions.

With the latch 124 in the half-latched position and activated fornon-revertible movement in the latching direction, the latch 124,although movable in the latching direction EE from the half-latchedposition to the fully-latched position, is not movable in the unlatchingAA direction past the half-latching position because engagement betweenthe pawl 202 and the latch control member 125 prevents rotation of therotationally connected latch 124 in the unlatching direction AA.Accordingly, the latch 124, unable to move in the unlatching directionAA to the unlatching position, latches the tailgate 118 to thesurrounding body 116 against the striker 126 in the near-closedposition. The control module 138 may then identify the accompanyinghalf-latching event, and in response to identifying the half-latchingevent, automatically operate the latch actuator 152 to move the latchcontrol member 125 and the attached latch 124 in the latching directionfrom the half-latched position to the fully-latched position.

For example, in response to identifying the half-latching event, thecontrol module 138 may operate the latch actuator 152 to rotate thepinion gear 210 in a direction which causes rotation of the matingsector gear 212 in direction BB. Rotation of the sector gear indirection BB produces an arcuate motion of the drive pin 214 indirection BB, until the drive pin 214 engages the latch lever 220. Onfurther rotation of the sector gear 212 in direction BB, the drive pin214 rotates the latch lever 220 in direction CC, forcing the latch lever220 into engagement with the latch control member 125. The rotatinglatch lever 220 then produces a rotation of the latch control member 125and the attached latch 124 in direction DD. This rotation may continueuntil the latch 124 reaches the fully-latched position, at which timethe rotationally-connected latch control member 125 has engaged anotherfeature of the pawl 202 designed to prevent back-rotation of the latchcontrol member 125 and latch in the unlatching direction AA and backtoward the half-latched position of the latch 124. The latch 124 is nowlocked in the fully-latched position (FIGS. 7A-7B) by engagement of theattached latch control member 125 with the pawl 202, and the tailgate118 is latched to the surrounding body 116 against the striker 126 inthe fully-closed position. As it moves in the latching direction fromthe half-latched position to the fully-latched position, the latch 124,drawing the striker 126 further into the tailgate 118, moves thetailgate 118 against the striker 126 from the near-closed position tothe fully-closed position.

In addition, referring to FIGS. 7A-8B and 10A-10B, and in one or morearrangements, the latch 124 may be structured so that, with respect tothe vertical plane V1, the centroid of the cross-section of the striker126 taken through the portion 126 p of the striker residing inside theslot 124 b resides along the first side S1 of the plane V1 when thelatch 124 is in a fully-latched position. In one or more particulararrangements, and as shown in FIGS. 7A-8B and 10A-10B, the latch 124 maybe structured so that, with respect to the vertical plane V1, the entirecross-section of the striker 126 taken through the portion 126 p of thestriker residing inside the slot 124 b resides along the first side S1of the plane V1 when the latch 124 is in the fully-latched position.

Referring to FIG. 7B, the latch may be structured so that an internalend 124 k of the slot 124 b resides along the first side S1 of the planeP1 when the latch 124 is in the fully-latched position. An internal endof the slot may be a location along an edge of the slot 124 b that isfarthest from an opening 124 m (FIG. 5B) of the slot into which thestriker 126 is received during operation of the latch. For example, inthe embodiment shown in the drawings, with the slot 124 b ending in acircular edge, the internal end of the slot 124 b shown in the drawingsmay be at the location 124 k on the circular edge farthest from the slotopening 124 m.

After the controller identifies the full-latching event, pinion gearrotation may be controlled to rotate the sector gear 212, pawl crank216, pawl lever 218, and latch lever 220 back to their respectivepositions in the idle configuration while the latch remains locked inthe fully-latched position (FIGS. 8A-8B).

Referring now to FIGS. 8A-13 , a process of unlatching and opening thetailgate will be described.

With the latch 124 in the fully-latched position engaging the striker126 and the pawl 202 engaged with the latch control member 125 (FIGS.8A-8B), the tailgate 118 creates a reactionary force operating betweenthe latch 124/latch control member 125/pawl 202 and the striker 126. Thereactionary force may be at least partially due to normal latchingforces, a weight component of the tailgate 118, etc. However, thereactionary force may also be at least partially associated withexternal loading, if any, on the tailgate. Tailgate external loading maybe loading arising from cargo loaded in the cargo bed and/or onto thetailgate and which exerts a force on the tailgate. When there isexternal loading on the tailgate 118, the reactionary force between thestriker 126 and the latch 124/latch control member 125/pawl 202increases to a level above the normal reactionary force due to latchingof the striker with no cargo loaded in the tailgate. Thus, as theloading acting on the tailgate increases, the force required todisengage the pawl 202 from the latch control member 125 may alsoincrease. If the pawl 202 is disengaged and the latch 124 released whenthe tailgate external loading is above a certain predetermined thresholdload, damage may occur to the tailgate, the cargo, and/or anotherportion of the vehicle.

The threshold load may be determined for a given vehicle design, forexample, based on calculation and/or iterative experimentation/producttesting directed to estimating types and magnitudes of tailgate externalloads above which an unacceptable amount of damage may be caused if thetailgate is allowed to open unattended responsive to an opening command.If an external tailgate loading has a magnitude above the predeterminedthreshold load, the tailgate 118 may be considered “overloaded”. FIG. 1Dshows one example of a condition in which cargo may overload the closedtailgate. In FIG. 1D, cargo 119 is shown bearing down on the closed andlatched tailgate 118.

For purposes of unlatching the tailgate 118, the latch actuator 152 maynormally be operated at a first predetermined nominal voltage specifiedso as to overcome the reactionary force to disengage the pawl 202 fromthe latch control member 125 when the latch 124/latch control member125/pawl 202 are acted upon by normal latching forces. The “firstpredetermined nominal voltage” may be a target or rated operationalvoltage of the latch actuator, recognizing that the actual operatingvoltage may vary within a small amount (for example, plus or minus 5%)from the rated voltage. The first predetermined nominal voltage of thelatch actuator 152 may also be sufficient to overcome the reactionaryforce to disengage the pawl 202 from the latch control member 125 evenif the tailgate 118 is what would be considered “overloaded”. Therefore,to prevent possible damage to the vehicle 100 and/or cargo, it isdesirable to prevent release of the latch and opening of the tailgate118 responsive to an opening command when the tailgate is overloaded.

The latch actuator 152 may normally be operated at the firstpredetermined nominal voltage for latching the tailgate. In certaincases, users may generate requests to automatically open the tailgate118 when, unbeknownst to them, there is loading on the tailgate.However, when the tailgate is overloaded, and the system automaticallyopens the tailgate, the cargo or vehicle may be damaged. Accordingly, inassociation with automatically opening the tailgate, the system forcontrolling the power tailgate 118 may be configured to overload checkthe tailgate using the latch actuator 152 whenever a remotely-generatedtailgate opening command is received. More specifically, responsive toreceiving a remotely-generated opening command, while the latch 124 isstill in the fully-latched position and prior to operating the latch torelease the tailgate 118, the control module 138 may control operationof the latch actuator 152 to overload check the tailgate 118 using thelatch actuator 152 to come to a determination whether the tailgate 118is overloaded or not overloaded. When the tailgate 118 is overloaded,the control module 138 may deny requests to automatically open thetailgate 118. The control module 138 may be configured to, under suchconditions, deny the requests to automatically open the tailgate 118,and instead, alert the users that the tailgate 118 is overloaded.Accordingly, the vehicle 100, including but not limited to the powertailgate system 142, as well as the cargo itself, does not suffer thethreat of damage.

FIGS. 8A-12B show various views of the latch assembly 120 from FIGS.5A-7B. As shown in FIGS. 8A-12B, for purposes of overload checking thetailgate 118, the latch assembly 120 and the tailgate 118 may beconfigured such that in addition to an unlatching position, ahalf-latched position and a fully-latched position, the latch 124 has anover-stroke position (shown in FIGS. 9A-9B) past the fully-latchedposition and in the latching direction EE. For instance, the latchassembly 120 and the tailgate 118 may be configured such that from theperspective of the latch actuator 152, the latch 124 is substantiallyunobstructed for movement in the in the latching direction from thefully-latched position to the over-stroke position. The unlatchingposition, the half-latched position, the fully-latched position and theover-stroke position may be consecutive in the latching direction and inthe unlatching direction. FIGS. 9A-9B show rotation of the latch 124from the fully-latched position (FIGS. 8A-8B) to the over-strokeposition (FIGS. 9A-9B).

In addition, referring to FIGS. 9A-9B and in one or more arrangements,the latch 124 may be structured so that, with respect to the verticalplane V1, the centroid Cl of the cross-section of the striker 126 takenthrough the portion 126 p of the striker residing inside the slot 124 bresides along the first side S1 of the plane V1 when the latch 124 is inthe over-stroke position. In one or more particular arrangements, and asshown in FIGS. 9A-9B, the latch 124 may be structured so that, withrespect to the vertical plane V1, the entire cross-section of thestriker 126 taken through the portion 126 p of the striker residinginside the slot 124 b resides along the first side S1 of the plane V1when the latch 124 is in the over-stroke position.

In particular arrangements, the latch may be structured so that theinternal end 124 k of the slot 124 b resides along the first side Si ofthe plane P1 when the latch 124 is in the over-stroke position.

In the context of the vehicle 100, the movement of the latch 124 and themovement of the tailgate 118 may have an interdependent relationship.That is, in correspondence with the unlatching position, thehalf-latched position, the fully-latched position and the over-strokeposition, the tailgate 118 and the surrounding body 116 may beconfigured such that in addition to one or more open positions, in whichthe tailgate 118 is unaligned with the surrounding body 116, anear-closed position, in which the tailgate 118 is near alignment withthe surrounding body 116, and a fully-closed position, in which thetailgate 118 is in alignment with the surrounding body 116, the tailgate118 has an over-closed position (shown in FIGS. 9A-9B) past thefully-closed position, which is associated with the over-stroke positionof the latch, and in which the tailgate 118 is past alignment with thesurrounding body 116. Thus, the latch is in the over-stroke position (or“overstroked”) when tailgate is in the over-closed position, and viceversa. The tailgate 118 and the surrounding body 116 may be configuredsuch that from the perspective of the latch actuator 152, the tailgate118 is substantially unobstructed for movement from the fully-closedposition to the over-closed position. In addition, as seen in FIGS.9A-9B, the latch actuator 152 may disengage the latch control member 125from the pawl 202 when the latch actuator attempts to move the latch 124to the over-stroke position (i.e., the pawl 202 is no longer in directcontact with the latch control member 125 during the process ofover-stroking the latch 124 and also if, and when, the latch reaches theover-stroke position).

In one or more arrangements, a switch (not shown) configured to detect ahalf-latching event (i.e., when the latch is in the half-latchedposition) may also be configured to detect if and when the latch 124reaches the over-stroke position.

In one or more arrangements, the tailgate 118 may be overload-checked bycontrolling operation of the latch actuator 152 to attempt to rotate thelatch 124 from the fully-latched position to the over-stroke position(i.e., by attempting to overstroke the latch). When attempting to rotatethe latch to the over-stroke position, the control module 138 may usepulse width modulation (PWM) to operate the latch actuator at a secondpredetermined nominal voltage that may be less than the firstpredetermined nominal voltage. The second predetermined nominal voltagemay be determined such that the resulting force produced by the latchactuator 152 will be sufficient to disengage the pawl 202 from the latchcontrol member 125 only if the reactionary force has a magnitude belowthe predetermined threshold load. Thus, the tailgate 118 may beprevented from opening responsive to a remotely-generated openingcommand if the tailgate is overloaded. In particular arrangements, thefirst predetermined nominal voltage is 12 volts. In particulararrangements, the second predetermined nominal voltage is 8 volts.

Although the process for overload checking is described with referenceto one tailgate actuator 150, and one latch actuator 152 andcorresponding latch assembly 120 and latch 124, it will be understoodthat this disclosure is applicable in principle to otherwise similarprocesses for one or more tailgate actuators 150, one or more latchactuators 152, one or more latch assemblies 120 and one or more latches124.

FIGS. 8A-9B shows operation of the latch assembly 120 in moving betweenthe fully-latched position and the over-stroke position of the latch 124to overload check the tailgate 118. FIGS. 9A-9B show the latch assembly120 in a configuration in which the latch 124 is in the over-strokeposition. FIGS. 10A-12B show a progression of the latch assembly 120 asthe latch control member 125 and the latch 124 are restored from thelatch over-stroke position (FIGS. 9A, 9B) to the fully-latched position(FIGS. 10A-10B). The pawl 202 is then rotated to release the latchcontrol member 125/latch 124 as previously described (FIGS. 11A-11B),allowing the latch control member 125/latch 124 to rotate in theunlatching direction AA (FIGS. 12A-12B) to the unlatched position of thelatch. FIG. 13 is a flow diagram showing a method of operation of thelatch assembly to overload check the tailgate.

Referring to FIGS. 8A-13 , starting in the fully-latched position of thelatch assembly 120 shown in FIGS. 8A-8B, as part of its evaluation ofthe information about the vehicle 100, the control module 138 monitorsfor and identifies a request to automatically open the tailgate 118.When the control module 138 does not identify a request to automaticallyopen the tailgate 118, it continues to monitor for requests toautomatically open the tailgate 118 in anticipation that a request toautomatically open the tailgate 118 will materialize.

In block 1102 (FIG. 13 ), the control module 138 may identify a requestto automatically open the tailgate 118. In block 1104, responsive to theidentification of a request to automatically open the tailgate 118, thecontrol module 138 may determine if the tailgate opening request wasremotely generated. If the tailgate opening request was not remotelygenerated, it is assumed that a user is in physical proximity to thetailgate 118 and can view the tailgate to determine whether or not it isoverloaded. Thus, under the assumption that the tailgate 118 is notoverloaded if the tailgate opening request was not remotely generated,the control module 138 may (in block 1114) control operation of thelatch actuator 152 to deactivate the latch 124. The control module 138may then (in block 1116) control operation of the tailgate actuator 150to open the tailgate 118.

Returning to block 1104, if the tailgate opening request was remotelygenerated, the control module 138 may (in block 1106), starting from thefully-latched position (FIGS. 8A-8B), operate the latch actuator 152 toattempt to move the latch control member 125/latch 124 in the latchingdirection from the fully-latched position to the over-stroke position(FIGS. 9A-9B). For instance, the control module 138 may operate thelatch actuator 152 to move the latch 124 in the latching direction untilit identifies an over-stroking event by activation of the half-latchedswitch as previously described. In one or more arrangements, the controlmodule 138 may use pulse width modulation (PWM) to operate the latchactuator at a lower voltage to over-stroke the latch according tooperation. In a particular arrangement, the latch actuator 152 may beoperated at a voltage of 8 V to over-stroke the latch 124, instead of atthe normal 12 V operating voltage. As it moves in the latching directionfrom the fully-latched position toward the over-stroke position, thelatch 124, drawing the striker 126 further into the tailgate 118, movesthe tailgate against the striker from the fully-closed position to theover-closed position.

Simultaneously with (or immediately after) beginning to move the latch124 in the latching direction from the fully-latched position, thecontrol module 138 may (in block 1108) start a timer. The timer may beconfigured to monitor a time elapsed from when the actuator starts toattempt to move the latch 124 from the fully-latched position to theover-stroke position. If the latch actuator 152 is unable to rotate thelatch to the over-stroke position after a predetermined time period, itis determined that an overload condition is affecting the tailgate 118.

After activation of the timer, the control module 138 may (in block1110) determine if the predetermined time period has elapsed. If thepredetermined time period has not elapsed, the control module 138 may(in block 1112) determine if the latch 124 has reached the over-strokeposition (i.e., the control module may determine if the half-latchedswitch has been activated). If the predetermined time period has notelapsed and the latch 124 has not reached the over-stroke position,control may return to block 1110. The loop 1110-1112 may continue whilethe predetermined time period has not elapsed and the latch 124 has notreached the over-stroke position. If the predetermined time period hasnot elapsed and the latch 124 has reached the over-stroke position, thecontrol module 138 may (in block 1114) determine that no overloadcondition affects the tailgate because the latch reached the over-strokeposition within the predetermined time period. Thus, the control modulemay deactivate the latch 124, allowing the tailgate to be opened (block1116).

Returning to block 1110, if the predetermined time period has elapsedand the latch 124 has not reached the over-stroke position, the controlmodule 138 may determine that an overload condition is affecting thetailgate 118. The control module 138 may then (in block 1118) controloperation of the latch actuator 152 to rotate the latch 124 back to thefully-latched position (FIGS. 10A-10B). When the latch 124 has returnedto the fully-latched position (block 1120), the control module 138 may(in block 1122) generate an alert configured to indicate to a user thatthe tailgate is overloaded.

Returning to FIGS. 10A-10B, if the tailgate is determined not to beaffected by an overload condition, and starting from the fully-latchedposition, the control module 138 may operate the latch actuator 152 todeactivate the latch 124 for movement in the unlatching directionresponsive to the tailgate opening request. For example, the pinion gear210 may be operated to rotate the mating sector gear 212 in direction FF(FIG. 3A) bringing the drive pin 214 into engagement with the pawl crank216. Further rotation of the sector gear 212 causes the drive pin 214 torotate the pawl crank 216 in direction BB. Rotation of the pawl crank216 in direction BB produces an opposite rotation (in direction FF) ofthe pawl lever 218 which is engaged by the pawl crank 216. Duringrotation of the pawl lever 218 in direction FF, the pawl lever 218engages the pawl 202 and forces the pawl to rotate out of engagementwith the latch control member 125 (FIGS. 11A, 11B), thereby allowing thelatch control member 125 and rotationally-connected latch 124 to rotatetoward the unlatching position (FIGS. 12A, 12B) under influence of thelatch control member biasing spring 200. This allows the tailgate 118 todetach from the striker. The control module 138 may then operate thetailgate actuator 150 to open the tailgate 118. As the tailgate 118 ismoved to the open positions, the striker 126 passes out of the tailgate118 through the striker chute 122. As it passes out of the tailgate 118,the striker 126, in combination with the bias for movement of the latchin the unlatching direction, moves the latch 124 in the unlatchingdirection to the unlatching position.

The control module 138 may then identify the accompanying unlatchingevent, and in response to identifying the unlatching event, may operatethe latch actuator 152 to control rotation of the pinion gear 210 torotate the sector gear 212, pawl crank 216, pawl lever 218, and latchlever 220 back to their respective positions in the idle configuration,thereby activating the latch 124 for non-revertible movement in thelatching direction.

With reference once again to FIG. 1C, as noted above, the processors134, the memory 136 and the control module 138 together serve as acomputing device whose control module 138 orchestrates the operation ofthe vehicle 100, including but not limited to the operation of thevehicle systems 130. The control module 138 may be a dedicated controlmodule for the power tailgate system 142, and may be housed, in whole orin part, in the tailgate 118. Relatedly, as part of a central controlsystem, the vehicle 100 may include a global control unit (GCU) to withwhich the control module 138 is communicatively connected.Alternatively, the control module 138 may be a global control module.Relatedly, as part of a central control system, the vehicle 100 mayinclude a global control unit (GCU) to which the control module 138belongs. Although the vehicle 100, as shown, includes one control module138, it will be understood that this disclosure is applicable inprinciple to otherwise similar vehicles 100 including multiple controlmodules 138.

Detailed embodiments are disclosed herein. However, it is to beunderstood that the disclosed embodiments are intended only as examples.Therefore, specific structural and functional details disclosed hereinare not to be interpreted as limiting, but merely as a basis for theclaims and as a representative basis for teaching one skilled in the artto variously employ the aspects herein in virtually any appropriatelydetailed structure. Further, the terms and phrases used herein are notintended to be limiting but rather to provide an understandabledescription of possible implementations. Various embodiments are shownin FIGS. 1-5B, but the embodiments are not limited to the illustratedstructure or application.

The flowcharts and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments. In this regard, each block in the flowcharts or blockdiagrams may represent a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

The systems, components and/or processes described above can be realizedin hardware or a combination of hardware and software and can berealized in a centralized fashion in one processing system or in adistributed fashion where different elements are spread across severalinterconnected processing systems. Any kind of processing system oranother apparatus adapted for carrying out the methods described hereinis suited. A typical combination of hardware and software can be aprocessing system with computer-usable program code that, when beingloaded and executed, controls the processing system such that it carriesout the methods described herein. The systems, components and/orprocesses also can be embedded in a computer-readable storage, such as acomputer program product or other data programs storage device, readableby a machine, tangibly embodying a program of instructions executable bythe machine to perform methods and processes described herein. Theseelements also can be embedded in an application product which comprisesall the features enabling the implementation of the methods describedherein and, which when loaded in a processing system, is able to carryout these methods.

Furthermore, arrangements described herein may take the form of acomputer program product embodied in one or more computer-readable mediahaving computer-readable program code embodied, e.g., stored, thereon.Any combination of one or more computer-readable media may be utilized.The computer-readable medium may be a computer-readable signal medium ora computer-readable storage medium. The phrase “computer-readablestorage medium” means a non-transitory storage medium. Acomputer-readable storage medium may be, for example, but not limitedto, an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer-readable storage medium would include the following: a portablecomputer diskette, a hard disk drive (HDD), a solid-state drive (SSD), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a portable compact disc read-only memory (CD-ROM), adigital versatile disc (DVD), an optical storage device, a magneticstorage device, or any suitable combination of the foregoing. In thecontext of this document, a computer-readable storage medium may be anytangible medium that can contain, or store a program for use by or inconnection with an instruction execution system, apparatus, or device.

Generally speaking, the control module 138 includes instructions thatmay be executed by the processors 134. The control module 138 may beimplemented as computer readable program code that, when executed by theprocessors 134, execute one or more of the processes described herein.Such computer readable program code may be stored on the memory 136. Thecontrol module 138 may be part of the processors 134, or may becommunicatively connected the processors 134.

Generally, modules as used herein include routines, programs, objects,components, data structures, and so on that perform particular tasks orimplement particular data types. In further aspects, a memory generallystores the noted modules. The memory associated with a module may be abuffer or cache embedded within a processor, a RAM, a ROM, a flashmemory, or another suitable electronic storage medium. In still furtheraspects, a module, as envisioned by the present disclosure, isimplemented as an application-specific integrated circuit (ASIC), ahardware component of a system on a chip (SoC), as a programmable logicarray (PLA), or as another suitable hardware component that is embeddedwith a defined configuration set (e.g., instructions) for performing thedisclosed functions.

Program code embodied on a computer-readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber, cable, RF, etc., or any suitable combination ofthe foregoing. Computer program code for carrying out operations foraspects of the present arrangements may be written in any combination ofone or more programming languages, including an object-orientedprogramming language such as Java™, Smalltalk, C++ or the like andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The program codemay execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer, or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

The processors 134 may be any components configured to execute any ofthe processes described herein or any form of instructions to carry outsuch processes or cause such processes to be performed. The processors134 may be implemented with one or more general-purpose orspecial-purpose processors. Examples of suitable processors 134 includemicroprocessors, microcontrollers, digital signal processors or otherforms of circuity that execute software. Other examples of suitableprocessors 134 include without limitation central processing units(CPUs), array processors, vector processors, digital signal processors(DSPs), field programmable gate arrays (FPGAs), programmable logicarrays (PLAs), application specific integrated circuits (ASICs),programmable logic circuitry or controllers. The processors 134 mayinclude at least one hardware circuit (e.g., an integrated circuit)configured to carry out instructions contained in program code. Inarrangements where there are multiple processors 134, the processors 134may work independently from each other or in combination with oneanother.

The memory 136 is a non-transitory computer readable medium. The memory136 may include volatile or nonvolatile memory, or both. Examples ofsuitable memory 136 includes random access memory (RAM), flash memory,read only memory (ROM), programmable read only memory (PROM), erasableprogrammable read only memory (EPROM), electrically erasableprogrammable read only memory (EEPROM), registers, magnetic disks,optical disks, hard drives or any other suitable storage medium, or anycombination of these. The memory 136 includes stored instructions inprogram code. Such instructions are executable by the processors 134 orthe control module 138. The memory 136 may be part of the processors 134or the control module 138, or may be communicatively connected theprocessors 134 or the control module 138.

While recited characteristics and conditions of the invention have beendescribed in connection with certain embodiments, it is to be understoodthat the invention is not to be limited to the disclosed embodimentsbut, on the contrary, is intended to cover various modifications andequivalent arrangements included within the spirit and scope of theappended claims, which scope is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures as is permitted under the law.

What is claimed is:
 1. A system for controlling a vehicle power tailgate comprising: a latch structured to be movable to a latching position when the latch is engaged with a portion of a tailgate so as to maintain the tailgate in a closed position associated with the latching position of the latch; a latch actuator operably connected to the latch to control operation of the latch; a processor; and a memory communicably coupled to the processor and storing a tailgate control module including instructions that when executed by the processor cause the processor to: responsive to receipt of a tailgate opening command, control operation of the latch actuator to attempt to move the latch to an over-stroke position of the latch; and responsive to a failure to move the latch to the over-stroke position within a predetermined time period, control operation of the latch actuator to move the latch to a fully-latched position of the latch.
 2. The system of claim 1 wherein the memory includes instructions that when executed by the processor cause the processor to, responsive to the latch reaching the over-stroke position within the predetermined time period, control operation of the latch actuator to release the latch, thereby enabling the tailgate to disengage from the latch and open.
 3. The system of claim 1 further comprising a switch configured to detect both a movement of the latch to a half-latching position and a movement of the latch to the over-stroke position.
 4. The system of claim 1 wherein the latch actuator is configured to operate at a first predetermined nominal voltage when the latch actuator is not attempting to move the latch to the over-stroke position, and wherein the latch actuator is configured to operate at a second predetermined nominal voltage less than the first predetermined nominal voltage when the latch actuator is attempting to move the latch to the over-stroke position.
 5. The system of claim 4 wherein the first predetermined nominal voltage is 12 volts.
 6. The system of claim 4 wherein the second predetermined nominal voltage is 8 volts.
 7. The system of claim 1 wherein the memory includes instructions that when executed by the processor cause the processor to, responsive to the failure to move the latch to the over-stroke position within the predetermined time period, generate an alert indicating that the tailgate is overloaded.
 8. The system of claim 1, wherein the memory further stores instructions that when executed by the processor cause the processor to: identify a request to automatically open the tailgate; identify whether the request to automatically open the tailgate is remotely generated or non-remotely generated; and responsive to the request to automatically open the tailgate being remotely generated, control operation of the latch actuator to attempt to move the latch to the over-stroke position.
 9. The system of claim 1 further comprising a latch control member rotationally connected to the latch and structured to be engageable by a pawl of the system to maintain the latch control member in a position associated with the latching position of the latch, and wherein the latch actuator is structured to disengage the latch control member from the pawl when the latch actuator attempts to move the latch to the over-stroke position.
 10. In a powered latch assembly for a vehicle tailgate, a method of checking for an overload condition of a tailgate secured in a closed condition by a latch prior to releasing the latch to enable opening of the tailgate, the method comprising steps of: responsive to receipt of a tailgate opening command, controlling operation of a latch actuator to attempt to move the latch to an over-stroke position of the latch; responsive to a failure to move the latch to the over-stroke position within a predetermined time period, controlling operation of the latch actuator to move the latch to a fully-latched position; and responsive to moving the latch to the over-stroke position within the predetermined time period, controlling operation of the latch actuator to release the latch to enable opening of the tailgate.
 11. The method of claim 10 wherein the latch actuator is configured to operate at a first predetermined nominal voltage when the latch actuator is not attempting to move the latch to the over-stroke position, and wherein the latch actuator is configured to operate at a second predetermined nominal voltage less than the first predetermined nominal voltage when the latch actuator is attempting to move the latch to the over-stroke position.
 12. The method of claim 11 wherein the first predetermined nominal voltage is 12 volts.
 13. The method of claim 11 wherein the second predetermined nominal voltage is 8 volts.
 14. The method of claim 10 further comprising a step of, responsive to the failure to move the latch to the over-stroke position within the predetermined time period, generating an alert indicating that the tailgate is overloaded.
 15. The method of claim 10 further comprising steps of: identifying a request to automatically open the tailgate; identifying whether the request to automatically open the tailgate is remotely generated or non-remotely generated; and responsive to the request to automatically open the tailgate being remotely generated, controlling operation of the latch actuator to attempt to move the latch to the over-stroke position.
 16. A non-transitory computer-readable medium for controlling operation of a vehicle power tailgate system to check a tailgate secured in a closed condition by a latch for an overload condition prior to releasing the latch to enable opening of the tailgate, the medium storing instructions that when executed by a processor cause the processor to: responsive to receipt of a tailgate opening command, control operation of a latch actuator to attempt to move the latch to an over-stroke position of the latch; responsive to a failure to move the latch to the over-stroke position within a predetermined time period, control operation of the latch actuator to move the latch to a fully-latched position; and responsive to moving the latch to the over-stroke position within the predetermined time period, control operation of the latch actuator to release the latch to enable opening of the tailgate.
 17. The computer-readable medium of claim 16 wherein the instructions further include instructions to, responsive to the failure to move the latch to the over-stroke position within the predetermined time period, generating an alert indicating that the tailgate is overloaded.
 18. The computer-readable medium of claim 16 wherein the instructions further include instructions to: identify a request to automatically open the tailgate; identify whether the request to automatically open the tailgate is remotely generated or non-remotely generated; and responsive to the request to automatically open the tailgate being remotely generated, control operation of the latch actuator to attempt to move the latch to the over-stroke position.
 19. The computer-readable medium of claim 16 wherein the latch actuator is configured to operate at a first predetermined nominal voltage when the actuator is not attempting to move the latch to the over-stroke position, and wherein the latch actuator is configured to operate at a second predetermined nominal voltage less than the first predetermined nominal voltage when the actuator is attempting to move the latch to the over-stroke position. 